Mal Couch edited a helpful volume on Titus called A Pastor’s Manual on Doing ChurchIt is an excellent expositional commentary and study tool. It may be out of print, but you may want to consider getting a used copy if you plan to preach through the Book of Titus. 

You may also be interested in the Kress title: The Pastoral Epistles for Pastors.

 The Pastoral Epistles for Pastors